Needle Cast Disease of Blue Spruce

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Norman Wolf, Retired San Juan County Extension Agent
Natalie Goldberg, Extension Plant Pathologist
Robert Cain, Forest Pest and Detection Specialist
College of Agriculture, Consumer and Environmental Sciences New Mexico State University
This Publication is scheduled to be updated and reissued 5/06.
DIAGNOSIS AT A GLANCE
Caused by
The fungus Rhizosphaera kalkhoffii
Symptoms
Needle discoloration: yellow to reddish-purple to brown
Premature defoliation
Premature death
Sign
Black pycnidia (fruiting bodies) develop on infected needles.
Disease conditions
Warm (65-75°F), wet weather
Disease management
Plant only healthy trees.
Avoid planting new trees next to established trees.
Sterilize pruning shears between cuts.
Promote good air circulation around trees by open spacing, selective pruning, and removing brush and grass around trees
Apply fungicide.
Rhizosphaera needle cast, a fungus disease caused by Rhizosphaera kalkhoffii, is affecting blue spruce (Picea pungens) trees in New Mexico. The disease has been identified in San Juan County, and spruce trees described with similar symptoms have been reported in other parts of the state.

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